Preparation of fresh fruit for market



Feb. 24, 1931.

v E. M. BROGDEN ET AL PREPARATION OF FRESH FRUIT FOR MARKET Filed March 2, 1925 O INVENTOR Ern 6:921 Broaden Ji zw Lrmw ,v'd a, M M

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Patented Feb. 24, 1931 UNlT STATES PATENT oFFlcE ERNEST M. BROGDEN, OF SANTA MONICA, AND MILES I. TROWIBRIDGE, OF PALMS, CALI- FOIRNIA, ASSIGNORS T BROGDEX COMPANY, OF WINTER HAVEN. FLORIDA, A COB- PORATION OF FLORIDA PREPARATION OF FRESH FRUIT FOR MARKET Application filed March 2, 1925. Serial No. 12.778.

This invent-ion relates to preparation of fresh fruit for market; and in particular it relates to the treatment of fresh fruits that are marketed and ordinarily consumed in uncooked condition, especially oranges, lemons, grapefruit, tangerines, and other citrus fruits, in such manner that the destructive action of molds and other organisms producing decay or rot is prevented or inhibited either wholly or to such a substantial extent as greatly to prolong the marketable life of the fruit; the complete treatment most desirably but not necessarily also including a stepbf providing the fruit with a very thin filmlike continuous coating of protective material comprising a waxy substance, such as paraffin for example.

The greatest present utility of the invention is in the treatment of fresh citrus fruits such as those above mentioned. The invention is also applicable, however, to the treatment of apples and other fruits that are attacked by mold or other rot organisms. Furthermore, the invention in its broader aspects extends to the treatment of vegetables, such as tomatoes or the like, that can be treated to advantage in accordance with the principles of the invention to be more fully here-- inafter set forth, and accordingly the term fruit as herein employed is not to be understood as restricted to fruit in the narrow sense of this word but rather in a broad sense to include vegetables as well.

It is a well-known fact that in the shipping and marketing of citrus fruits, for example, heavy losses occur through decay in the form of blue mold rot, stem end rot, and other forms of rot to which oranges and the like are subject to a greater or less extent. Dccay in commercial shipments of citrus fruits amounts very commonly to from to per cent, and in many instances it isconsiderably higher, often running as much as to per cent it the fruit is Weak as it is at certain seasons. Blue mold is responsible for the greater part of these decay losses. It is also well-known that until recently no practical solution of the problem of preventing or controlling the destructive action of blue mold and the like has been known, notwithstanding prolonged study and investigation of the problem by recognized experts in the art extending over many years. Careful handling of the fruit in picking and packing, in order to avoid scratches, bruises and other mechanical injuries, and thus to reduce the liability to infection by blue mold spores, has been the principal suggestion of value that such experts have advanced; and while the percent age of decay in fruit shipments can in some measure be ke 1: down by careful handling, it cannot there y be eliminated or prevented from being large in many instances. Shipment under ice, involving precooling and refrigeration, has also been suggested and serves to temporarily check blue mold growth while the fruit is in transit to market, but upon removal from refrigeration, the. blue mold develops at an accelerated rate and de-- struction of infected fruit is even more rapid than where refrigeration has not been used. Refrigeration therefore is in effect merely an expedient for transferring the loss from the shipper to the receiver. i i

It has been found by the present applicants that an aqueous solution of an alkali metal carbonate, specifically sodium carbonate, it employed in concentrations equivalent to not less than 2 ounces of Na CO per gallonis eiiective to materially reduce decay in citrus fruits due to blue-mold or the like, especially if the fruit be subjected to the action of the treating solution while the solution is moderately warm, temperatures between 100 and 120 F. being suitable and around 115 F. being good average practice. The invention is not limited to the employ ment of an alkali metal carbonate since it is possible by exercising proper care to obtain reduction of blue mold by the action of a solution containing an alkali metal hydrate, such as sodium hydrate; but care must be taken that if caustic alkali be employed in the solution, it must not be in such concentration as to burn the skin of the fruit or otherwise adversely to affect its appearance or quality. In general, however, the alkalinity of a solution used in accordance with the principles of the invention should be at least as great as is equi;alent to a content of 2 ounces of sodium carbonate per gallon.

In the practice of the present invention, the employment of sodium carbonate in the form of commercial soda ash is especially to berecommcnded. A solution containing 6 ounces of soda ash for each gallon of water possesses marked mold-inhibiting properties especially when appliedto the fruit at a temperature approximating 115 F. and allowed to remain in contact therewith for at least two or three minutesl Most desirably the treating period should be five minutes or more in length since a better opportunity is thus afiorded for the warm solution to thoroughly impregnate exposed rind tissues with the alkaline mold-inhibitingagent. It is seldom necessary that the treating period total more practice. The treatment may advantageously include thoroughly rubbing or scrubbing the fruit while it is wet with the treating solution since this facilitates thorough impregnation of the exposed rind tissues and ghus Celanhances the mold-inhibiting effect prouce While a strength of 6 ounces of sodium ca rbonate to the gallon has been referred to as a desirable concentration, it is to be understood that this is merely typical of good practice and is not restrictive. A strength of 3 or 1 ounces per gallon has a very substantial protective etfect, particularly when the solution is applied warm and the treatment is prolonged to a total of ten or fifteen minutes. 0n the other hand it is undesirable to employ too concentrated a solution as the effect of such a solution upon the appearance of the fruit is sometimes undesirable. Usually it is not advisable or necessary to use more than 12 ounces of soda ash to the gallon, and as a rule the use of from 5 to 8 ounces to the gallon is better practice.

The results obtained in the practice of the invention are usually most satisfactory where the fruit is initially treated with the alkaline solution before it has been washed or otherwise wetted with water or other liquid of non-mold-inhibiting character. This is because the exposed rind tissues of the fruit are ordinarily dried out or partially dried out by the time the fruit is to be put through the sequence of packing house operations and therefore are in a highly absorptive condition and ready to take up with avidity any liquid with which the fruit is brought into contact. By avoiding any wetting of the fruit prior to treatment with the mold-inhibiting solution, said solution can be relied upon to penetrate and impregnate the absorptive exposed rind tissncs in its full strength and thus exercise a maximum mold-inhibiting effect; whereas if the exposed rind tissues are more or less saturated with wash water or the like before treatment with the alkaline solution,

After treatment with the alkaline mold-in hibiting solution, the fruit may desirably be provided with a very thin film-like protective coating of waxy material for the purpose of maintaining the fruit in firm, plump and unwithered condition. While this further treatment of the fruit is not an essential feature of the invention in its broader aspects, it offers distinct advantages especially during those parts of the shipping season when the fruit is very ripe.

While the process of the invention may be carried out with the aid of various types of apparatus, one desirable practical form of apparatus installation that gives satisfactory results in treating oranges, for example, is shown more or less schematically and dia grammaticall in side elevation in the accompanying drawing. In using this apparatus system to carry out the new process, fruit, which in this particular instance will be assumed to be unwashed fruit just as it is received from the grower, is delivered over chute board 10 into wash tank or soaking tank 11 containing a water solution of sodium carbonate prepared by dissolving commercial soda ash in water in the proportion of about 6 ounces of soda ash per gallon, for example, the level of the liquid in the tank being indicated at 12. The solution may be suitably warmed, to a temperature of around 115 to 120 F. forexample, bysuitableheatingmeans such as steam coils 13. The fruit dumped into the soaking tank 11 floats gradually toward an elevator of any suitable type, conventionally indicated at 14, the fruit being thoroughly wetted with the treating solution en route. The elevator conducts the wet fruit up out of the tank and delivers it over chute board 15 to a fruit washer 16, which in the present instance comprises rotary cylindrical brush rolls 17 mounted substantially in the same plane-and cooperating in one or more pairs to provide a fruit runway or runways inclined slightly downward from the receiving end of the washer device. As the fruit passes down along the brush rolls it is thoroughly rubbed thereby and at the same time is sprayed with more of the warm treating solution supplied through overhead spray jets 18 by a pump 19 which draws its supply through pipe 20 from soaking tank 11. The

' excess solution falls from the brushrolls of the fruit washer into a drip pan 21 and is returned through pipe 22 to the soaking tank. A drip board 23 is also provided to return drip from the elevator 14 to said tank.

After receiving a thorough rubbing and scrubbing in the washer 16, the cleansed and treated fruit is delivered over a chute board 24 to suitable conveyor means indicated conventionally at 25. Advantageously this conveyor means may be of such character and arrangement that the fruit, wet with the sodium carbonate solution, remains upon it for a substantial period of time sufficient to ensure thorough and eilicient action of the moldinhibiting agent on the fruit. Said conveyor may therefore be relatively long and may also advance the fruit circuitously to the next stage of operations. The conveyor discharges fruit over chute board 26 to a drier of any well known suitable type indicated conventionally at 27. In order to avoid having the surface of the fruit rendered uncommercial by unsightly deposits of solid mineral matter as a result of the treatment with sodium carbonate, it is sometimes advantageous, although not essential in the broader aspects of the invention; to subject the fruit, prior to its entry into drier 27, to a carefully restricted and controlled rinsing with plain water to remove superficial excess of the sodium carbonate. This may be accomplished, for instance, by locating a rinsing or sprinkling device over the conveyor 25 slightly in advance of the point at which it delivers fruit to the drier. In the present example, the device may compri'se a small tank 28 having a line of discharge outlets 29 in its bottom extending transversely of said conveyor. Plain water is supplied to the tank through pipe 30 and a constant level is maintained in the tank by means of float-controlled valve 3 In this way exactly the right amount of rinsing water may be showered on the fruit as it passes under the rinsing device.

In the drier 27, the sensible surface moisture of the fruit is removed. If the fruit was rinsed before being dried, as in the typical example just given, it usually requires no further treatment before application of the waxy protective material which, as already indicated, is optional although desirable. lVhere the fruit has not been so rinsed, however, and in cases where the rinsing is not so complete as to certainly preclude the possi' bility of some substantial mineral depositon the dry surface of the fruit, it is desirable to provide means for removing all or substantially all of such surface deposit prior to applying the waxy protective material. To this end, the fruit leaving drier 27 may be (le livered over chute board to suitable brnshing and rubbing means which may desirably be of the brush roll type indicated generally at 33, the general construction of which may be similar to the washer unit 16, the spray heads being omitted, however, and the surface of the rotary brush rolls being advantageously of soft bristles such as horsehair. The white powder deposit of mineral matter which may be left on the surface of the fruit after it has passed through the drier, is dusted off by these rolls which may be driven at relatively high speed.

From the brush roll mechanism 33, the fruit then rolls down over chute board 34 to another brush roll mechanism indicated generally at 35, above which, near the upper or receiving end, is located suitable spraying means, such as air brushes indicated conventionally at 36, said air brushes serving to spray fluid coating material in small quantity down upon the fruit as it enters units 35. Most desirably this coating material comprises parafiin and a light mineral oil solvent thereof thoroughly intermingled to provide a thinly fluid mixture that can be spread in an extremely thin film over the. fruit by the action of the brush rolls.

After receiving a small amount of. coating material from the air brushes upon entering brush roll unit 35, the fruit continues to pass down the brush roll runway or runways and is subjected to a very thorough rubbing by the horsehair surfaces thereof, the coating material applied to each fruit being spread out into an extremely thin protective film coating. Upon leaving unit 35, the fruit passes over -chute board 37 and may optionally travel through a fruit drier 38 where the solvent in the paraflin composition, if a volatile solvent is employed, may be evaporated to a greater or less extent. Leaving the drier over chute board 39, the fruit then goes to the graders and sizers and is ready to be shipped in the usual manner except that precooling and refrigeration are unnecessary, provided the cars in which the fruit is shipped are reasonably well ventilated. Precooling and refrigeration are also unnecessary where the fruit does not receive an application of paraffin composition.

Where it is desired to apply the treating so- ;lution to the fruit under pressure, this may be effected in various ways. For instance, the passage of the fruit through the tank 11 may be so regulated and controlled as to cause the fruit to pile up several layers deep in the treating tank, thus subjecting the lower layers to a hydrostatic pressure corresponding to a submergence of say 18 inches to 2 feet or more, and provision may be made to agitate the fruit in the tank in such manner as to cause the upper and lower layers of fruit to exchange places and thus expose all the fruit passing through the tank to the aforesaid hydrostatic pressure of the treating solution It is also feasible to employ mechanical means indicated in the drawings.

a. of themselves aids efliciently in cleansing to maintain the fruit submerged well below the surface of the solution throughout its travel through the tank 11 which, of course, may be much longer than is diagrammatically Such expedients for applying the solution under pressure require no further explanation here as in and they constitute no part of the present invention.

An alkaline reagent of the character of sodium carbonate not only exercises a pronounced mold-inhibiting action when em ployed in accordance withthe principles of the invention as above set forth, but it also the fruit from adherent foreign matter especially if this be of airoily character as it frequently Its primary function in the practice of the invention, however, is its mold-inhibiting acac tion as hereinbefore pointed out.

The present application contains subject matter divided out of our prior copending application Serial No. 657,215, filed August 13, 1923, now Patent 1,529,461, granted March 10, 1925, and is a continuation in part thereof.

What is claimed is:

1. in the preparation of fresh fruit for market, the process of protectively treating the fruit for prevention of blue mold decay and the like, which comprises subjecting the fresh fruit to the action of a warm aqueous mold-inhibiting solution possessing a degree of alkalinity at least as high as that equivalent to the employment of 2 ounces of soda ash per gallon of water.

2. In the preparation of fresh fruit for market, the process .of protectively treating the fruit for prevention of blue mold decay and the like which comprises subjecting the fresh fruit to the action of an aqueous moldinhibiting solution containing not less than ounces of sodium carbonate per gallon.

In the preparation of fresh fruit for -market, the process of protectively treating the fruit for prevention of blue mold decay and the like which comprises subjecting the fresh fruit to the action of an aqueous moldinhibit-ing solution containing between 2 and 12 Ounces of sodium carbonate per gallon.

t. In the preparation of fresh citrus fruit for market. the process which comprises subjcctingthe fresh fruit to the action of an aqueous mold-'nhibiting solution containing between 2 and 12 ounces of sodium carbonate per gallon. said solution being maintained at a temperature above 100 F. but insufficiently high to scald or cook the fruit, and the fruit remaining wet with said solution for from 2 to 15 minutes.

5. in the 'irepara :11 of fresh citrus fruit for market, the process set forth in claim 4: further characterized by the fact that said mold-inhibiting solution contains approximately 6 ounces of sodium carbonate per gallon and that the fruit remains in contact therewith for at least 5 minutes.

6. In the preparation of fresh fruit for market, the process as defined in claim 4t further characterized by the fact that said fruit is subjected to the stated treatment without previous washing or wetting with a niin-mold-inhibiting liquid.

7. In the preparation of fresh fruit for market the process set forth in claim -i further characterized by the fact that said moldinhibiting solution contains approximately 6 ounces of sodium carbonate per gallon and that the fruit remains in contact therewith for at least five minutes. the stated treatmentbeing applied to the fruit without previous washing or Wetting thereof with a non-moldinhibiting liquid.

8. In the preparation of fresh fruit for market, the process which comprises subjecting fresh fruit to the action of an aqueous solution containing at least 2 ounces of sodium carbonate per gallon, said solution beingapplied in heated condition with the aid of pressure.

in testimony whereof we hereunto afiix our signatures.

ERNEST M. BROGDEN. MILES L. 'lROlVBRIDGE. 

